But don't get too excited—it only works at high temperatures.

Lithium batteries have become a very popular technology, powering everything from cell phones to cars. But that doesn't mean the technology is without its problems; lithium batteries have been implicated in some critical technological snafus, from exploding laptops to grounded airplanes. Most of these problems can be traced back to the electrolyte, a liquid that helps ions carry charges within the battery. Liquid electrolytes can leak, burn, and distort the internal structure of the battery, swelling it in ways that can lead to a catastrophic failure.

The solution, of course, would be to get rid of the liquids. But ions don't tend to move as easily through solids, which creates another set of problems. Now, researchers have formulated a solid in which lithium ions can move about five times faster than any previously described substance. Better yet, the solid—a close chemical relative of styrofoam—helps provide structural stability to the battery. Don't expect to see a styrofoam battery in your next cellphone though, as the material needs to be heated to 60°C in order to work.

The problem with liquid electrolytes has to do with the fact that, during recharging, lithium ions end up forming deposits of metal inside the battery. These create risks of short circuits (the problem that grounded Boeing's Dreamliner 787) and can damage the battery's structure, causing leaks and a fire risk. Solid electrodes get around this because the lithium ions will only come out of the electrolyte at specific locations within the solid, and can't form the large metal deposits that cause all of the problems.

However, as noted above, solids don't allow lithium to move through them very easily. This creates a bit of a practical problem, in that the batteries typically need to be heated to around 80°C before charges start moving at all, but long-term performance problems are even worse. Because the ions move so slowly, a gradient of lithium gets built up across the battery during discharging, with ions piling up near the negative electrode. This slows the rate at which they can charge and discharge.

The key thing about the new material is that it avoids having a single, charged site where the lithium ions would be stored, since this strong attraction is what slows the ions down. Instead, each of the polystyrene groups has an added chemical that includes two sulfur atoms bridged by a nitrogen. Although the nitrogen technically carries a negative charge, it's shared with the two sulfurs, making it far more diffuse. As a result, it doesn't hang on to the lithium as tightly, meaning the lithium can move through the material much faster.

Almost everything about the material is an improvement over existing solid electrolytes: rather than needing temperatures of 80°C to operate, it works well at 60°C; the ions move about five times faster than they do in existing electrolytes; and the polystyrene-based electrolyte has a tensile strength ten times that of the existing material.

The researchers built a number of test batteries with this, and showed that the material was stable for dozens of charge/discharge cycles, and operated well over a wide variety of temperatures (though all of them a bit elevated). There were a few performance numbers but, given the unusual electrodes and battery material in this case, it's hard to make a comparison between them and the existing liquid electrolyte batteries.

In the end, the comparisons might not be especially relevant. Because these batteries require elevated temperatures just to operate, they're not going to find the same uses as our current gadget batteries. But there are a number of use cases—like in aircraft, for just one example—where keeping batteries at an elevated operating temperature wouldn't be an issue. And that also happens to be a use case where the things this battery does bring to the table, like mechanical strength and limited risk of fires or explosions, may make a somewhat lower performance worth putting up with.

I would like to note that there are ceramic materials that have room temperature ionic conductivities near to or equaling the current liquid electrolytes. The current record holder AFAIK was first described in this paper (sorry, it's another paywall). One huge caveat with that material though is that it forms hydrogen sulfide gas on contact with water (although not all ceramics have that issue). Ceramics have additional problems with the fact that they're, well, ceramic and therefore very brittle.

I haven't had a chance to read through this paper, but most solid polymer electrolytes (which this paper is about) do require heating to 60-80 C to get acceptable performance. The standard material is polyethylene oxide (PEO) which has to be melted to operate reasonable (~60 C), although there are a number of tricks one can do to make it work better (but not good enough) at room temperature.

This is a pretty cool development and I'll be reading through this paper more carefully when I get a chance.

In the United States, several research groups are doing work on sulfur impregnated mesoporous carbon, which also work as well.

That's a technique to prevent the polysulfide shuttle, specific to lithium sulfur batteries you're describing. This paper is much more important, as it's about the lithium conductor and applies to all lithium batteries.

AreWeThereYeti wrote:

Just as a note, in the battery industry, "lithium battery" without a "-ion" or "polymer" qualifier means a primary, non-rechargeable battery.

Edit: Your point stands that "lithium battery" is misused in the first paragraph of the article.

Lithium battery means a battery with lithium metal. Currently, only primary, non-rechargeable lithium batteries are practical, but this type of material would resolve one of the major reasons why we don't have rechargeable lithium metal batteries. I recharge batteries with lithium metal all the time in lab, but they aren't used long enough to short due to dendrites, so it's not an issue.

In the United States, several research groups are doing work on sulfur impregnated mesoporous carbon, which also work as well.

That's a technique to prevent the polysulfide shuttle, specific to lithium sulfur batteries you're describing. This paper is much more important, as it's about the lithium conductor and applies to all lithium batteries.

AreWeThereYeti wrote:

Just as a note, in the battery industry, "lithium battery" without a "-ion" or "polymer" qualifier means a primary, non-rechargeable battery.

Lithium battery means a battery with lithium metal. Currently, only primary, non-rechargeable lithium batteries are practical, but this type of material would resolve one of the major reasons why we don't have rechargeable lithium metal batteries. I recharge batteries with lithium metal all the time in lab, but they aren't used long enough to short due to dendrites, so it's not an issue.

Edited word choice

Fine, but my point stands, which is that the rechargeable batteries discussed in this article are not normally referred to as "lithium batteries", they are either lithium-ion or lithium-polymer.

In the United States, several research groups are doing work on sulfur impregnated mesoporous carbon, which also work as well.

That's a technique to prevent the polysulfide shuttle, specific to lithium sulfur batteries you're describing. This paper is much more important, as it's about the lithium conductor and applies to all lithium batteries.

AreWeThereYeti wrote:

Just as a note, in the battery industry, "lithium battery" without a "-ion" or "polymer" qualifier means a primary, non-rechargeable battery.

Edit: Your point stands that "lithium battery" is misused in the first paragraph of the article.

Lithium battery means a battery with lithium metal. Currently, only primary, non-rechargeable lithium batteries are practical, but this type of material would resolve one of the major reasons why we don't have rechargeable lithium metal batteries. I recharge batteries with lithium metal all the time in lab, but they aren't used long enough to short due to dendrites, so it's not an issue.

You mention: "The ions moved about five times faster than they did in the existing electrolytes." But, then mention that this new electrolyte has lower performance. Did you mean only other "solid" existing electrolytes, but not the common liquid? Or, did you mean decreased performance in relation to operating temperature--or some combination of both?

Jokes aside, when lithium-ion/polymer batteries catch fire it is usually because if you over- or undercharge them, the lithium metal migrates and forms tiny tree-like (i.e. dendritic) structures that can pierce the separator membrane in the battery, causing a short (and thus a fire). That's why they have to have special monitoring circuits that try to prevent that from happening, and if it does, the circuit needs to permanently disable the battery so additional charging doesn't cause a fire.

edit: and this is also why a lot of people, me included, are incredulous they are trying to use such big, dense high-power lithium-ion batteries that clearly haven't been designed or tested properly in a commercial AIRPLANE. Even the new "fixed" batteries are being rushed into service way too quickly, clearly because of commercial and political/reputational pressure on Boeing and the FAA. You won't catch me on a Dreamliner until these have been running for YEARS without any problems. The FAA isn't doing it's job properly (nothing new there).

Can someone please clear this up for me... I was under the impression that the problem with Lith-Ion batteries failing catastrophically had to do with the fact that most of them in the market are Lithium Cobalt and that the cobalt electrode is the problem, instead of other compounds that are inherently safer like Lithium iron phosphate or lithium manganese.

Why is this article only talking about the electrolyte and not the electrode?

edit: Do the Boeing batteries use Lithium Cobalt? If so, why wouldnt they use a different chemistry with a better safety profile?

I'd love to see a grid of the different stats on the different kinds of batteries discussed here. E.g. in the categories of Operating Temperature, Charge Rate, etc, show how the Liquid Lithium, New Solid Lithium, and Old Solid Lithium compare.

Is this solid electrodes battery technology any different to what the government has been using for decades? I heard that the military have been using this solid electrodes in military equipments for years. There's these military jets are using battery driven drive chain instead of the use of the conventional engines. It is so quiet that you would not even noticed its presence when it's over and a few feet above you. Another sayings, There are Russian's warships run by this type of batteries. It is said that this solid electrodes battery has been classified by the U.S. as top secret and was not allowed to be used in private businesses.

Should be using LiFePO4 electrode materials, especially for applications where safety and reliability are important. It has a somewhat lower capacity than LiCoO2 fresh off the manufacturing line, but after a year on the shelf or 50 charge cycles or a few temperature changes it has a much higher real capacity. It is also intrinsically safer, the structure is much more stable and it won't release cause fires when overheated. It is also less toxic.

I really don't see why this battery chemistry has been neglected. I suspect its purely marketing departments don't like the lower off the shelf energy density than LiCoO2, even though in reality most users will get much longer battery life throughout its lifecycle.

Is it just another dangerous triumph of marketing over technology or does anyone know a good reason it's not more widely used?

PS: I'm aware I'm somewhat off topic from the article, this has been bugging me for a while now.

Don't worry, I won't. If I had a dime for every article I've seen about new battery technology, I'd be rich. This is one of the slowest areas of technology growth, but you could hardly tell it by the number of "coming soon!" battery articles out there.

Is this solid electrodes battery technology any different to what the government has been using for decades? I heard that the military have been using this solid electrodes in military equipments for years. There's these military jets are using battery driven drive chain instead of the use of the conventional engines. It is so quiet that you would not even noticed its presence when it's over and a few feet above you. Another sayings, There are Russian's warships run by this type of batteries. It is said that this solid electrodes battery has been classified by the U.S. as top secret and was not allowed to be used in private businesses.

In a word, "nope". At least not unless you also want to believe in Aurora flying disc aircraft powered by technology recovered from crashed UFOs, at which point it's all just magic. Nobody has an inkling of a battery technology with a power density to rival hydrocarbon fuels, which is why everything practical that flies today has an oil/petrol burning engine. Even in a post-oil world of fusion electricity and hydrogen cars it looks likely that aircraft will still use some form of hydrocarbon, perhaps synthesised using electricity.

So, are you saying my cell phone battey has liquid in it? No matter how hard I shake it, I cannot hear any liquid movement. I am going to have to cut one open to see. I have never had any sense that cell phone batteries were anything but solid.

So, are you saying my cell phone battey has liquid in it? No matter how hard I shake it, I cannot hear any liquid movement. I am going to have to cut one open to see. I have never had any sense that cell phone batteries were anything but solid.

Another day, another article about some promising new battery technology. 10 years ago I was saying that in 10 years, batteries will be radically better, solve the intermittency issues with solar power and bury OPEC. I'm still saying the same thing, but I've changed my tune to 50 years instead of 10. I wish these breakthroughs would arrive sooner, but I guess the thing must take its course.

Is this solid electrodes battery technology any different to what the government has been using for decades?

Yes.

You are referring to "thermal batteries". Basically you take a normal liquid-based battery, freeze it, grind it up, press it into pellets, and put it in a case with a bit of thermite. To use it, you spark the thermite which melts the battery components back into a liquid and the battery runs for a short period. As long as its cold, it can remain on the shelf for years with a "full charge".

First used on the V2 missile, used since then on lots of missile systems and similar "one shot" systems.

You are referring to "thermal batteries". Basically you take a normal liquid-based battery, freeze it, grind it up, press it into pellets, and put it in a case with a bit of thermite. To use it, you spark the thermite which melts the battery components back into a liquid and the battery runs for a short period. As long as its cold, it can remain on the shelf for years with a "full charge".

First used on the V2 missile, used since then on lots of missile systems and similar "one shot" systems.

That is a crazy sounding system! Do you have any links to good reading material on it?

I'd like to know what's going on with lithium nickel batteries. A few years ago, there was work done on this in a university here. A link I had is now 404'd, so I can't get to it. Sony had licensed this tech, but I've found nothing since. There are some batteries, such as the ones Panasonic are going to make for Tesla, but those are not the same.

This is all I've found with a quick look, but it doesn't seem up to date:

You are referring to "thermal batteries". Basically you take a normal liquid-based battery, freeze it, grind it up, press it into pellets, and put it in a case with a bit of thermite. To use it, you spark the thermite which melts the battery components back into a liquid and the battery runs for a short period. As long as its cold, it can remain on the shelf for years with a "full charge".

First used on the V2 missile, used since then on lots of missile systems and similar "one shot" systems.

That is a crazy sounding system! Do you have any links to good reading material on it?

The V craft battery was a molten salt battery.Wiki: Molten Salt BatteryPrimary batteries are the ones in common use. They are activated by raising their temp to operating levels. When kept "cold" they are inert and do not lose chargeSecondary batteries are rechargeable and use liquid sodium. High temperatures and sodium's antisocial behavior make these very consumer unfriendly.

The sources for the Wiki provide a link to this quick blurb on a Low Temp Molten Salt battery that is still under development with a planned release in 2015 (no details in this announcement)The patent on the Low Temp Molten Salt battery is here.

This "low temp" battery has an operating temperature of 135F+ so it remains to be seen how useful this will be in small portable devices.